1. Field of the Invention
The present invention relates particularly to organic coating compositions useful for both permanent and temporary protection of metal parts such as cold rolled steel. More particularly, the organic coating compositions of this invention generally are classified 106, particularly in subclasses 14.11, 14.13, 14.15, 14.16, 14.34, 14.35, 14.37, 14.38, 270, 271, and 272.
2. Description of the Prior Art
U.S. Pat. No. 3,539,367 to Yaroshevich, et al discloses a wax emulsion containing a salt of an organic acid and an amine. U.S. Pat. No. 3,660,128 to Sheldahl teaches an alkanolamine and an aliphatic carboxylic acid in the preparation of a semi-solid wax-in-water emulsion. U.S. Pat. No. 2,349,326 to Wilson teaches a combination of morpholine and a fatty acid to emulsify waxy materials in water for paste-type waxes. U.S. Pat. No. 3,125,453 to Simmonds employs a mixture of triethanolamine and an acid to emulsify a mixture of waxes also for paste-type polishes.
U.S. Pat. No. 4,035,514 to Davis, teaches a water-dispersible petrolatum composition containing cetyl alcohol, lanolin alcohols and alkoxylate fatty acids esters of sorbitol.
Most of the above teach production of temporary coatings such as floor waxes, cosmetics and the like. In contrast, the present invention, possibly through the use of co-solvents which tend to form azeotropes which enhance water removal during curing, provides coatings having substantial life even in corrosive environments. While not wishing to be bound to any theory or mechanism, it appears the co-solvents tend to act as dispersing agents and additionally enhance stability of the liquid compositions at low temperatures.
Also, the inclusion of the salts of organic acids in the present invention tend to build longer-chain molecules which additionally deter corrosion and promote stability.
The coatings of the present invention find additional utility as lubricants, e.g. particularly for wire drawing and other metal drawing, extrusion and impact forming operations.
In brief review, other prior U.S. patents of interest include:
U.S. Pat. No. 3,539,367 to Yaroshevich, relates to cationic emulsions (the compositions of the present invention are not cationic emulsions);
U.S. Pat. No. 3,660,128 to Sheldahl, relates to inverted wax emulsion pastes for artwork;
U.S. Pat. No. 2,349,326 to Wilson and 3,125,453 to Simmonds, both relate to paste-type polishes;
U.S. Pat. Nos. 2,862,825 to Westlund et al, 2,943,945 to Saywell, and 3,565,843 to Kassinger, all relate to soluble oils not to firm wax coatings;
U.S. Pat. No. 3,434,851 to Miller, relates to solvent-borne asphalt coatings;
U.S. Pat. Nos. 3,446,765 to Phillips, 3,699,065 to Clark, 4,184,991 to Scheurman III, 3,223,666 to Botton, 3,379,548 to Jen, 4,039,495 to Hunsucker, 4,051,089 to Tobias and 4,081,441 to Hunsucker, all relate to base resin formulas not to completed coatings;
U.S. Pat. No. 3,494,882 to Andrews, relate to high gloss emulsified polyester emulsions;
U.S. Pat. No. 4,187,204 to Howard, relates to water-borne paint containing not over 10% water;
U.S. Pat. No. 4,225,477 to Vosishth and Wang, relate to co-solvent changes in water-borne coatings to control re-coatability (the coating's ability to form a substrate for a topcoat);
U.S. Pat. No. 4,148,948 to Williams, relate to a leveling additive for water dispersible paints; and
U.S. Pat. No. 3,413,227 to Howard and Randell, relate to substituted benzotriazole.
Other patents considered in preparing this application are: U.S. Pat. Nos. 3,879,335, Storck, et al 2,695,910, Asseff, P.A., et al 3,565,678, Johnson, et al 4,239,648, Marshall, et al 4,059,452, Nishijima, et al 3,653,931, Burchart, et al 3,985,584, Chan, et al 4,048,374, Kotzach, et al 3,839,051, Carreny, L. 3,903,346, Delcon, et al 3,864,322, Yalloorakis, M. D. 4,062,821, Hung, T. M. 3,773,550, Tomalia, D. A. 4,035,514, Davis, R. I. 4,162,920, Gillich, T. N. 3,661,796, Erby, et al 3,313,635, Wollak, et al 8,080,221, Fessler, et al 3,738,851, Jarvis, W. H. 3,726,807, Johnson, K. L. 3,642,653, Northan et al.
Problems with protective coatings for metals, especially those primarily intended for long-term storage protection, have always existed. Prominent difficulties have been tackiness, poor water removability, sensitivity to water, objectionable odor, and, where water-borne compositions are involved, limited high-temperature storage stability of the compositions themselves.
In general, the main benefit of a water reducible coating is that it reduces the amount of organic volatiles that are given off during a coating process. Another advantage is that use of such materials is safer both for people and for the environment.
Any water reducible composition involving an emulsion must have sufficient storage stability in order to have practical commercial applications. For example, a drum of a water reducible emulsion must remain homogeneous for a sufficient amount of time after packaging to permit use by an end use customer, who in turn may have to store the drum in this inventory prior to his use.
It is an object of this invention to provide a sufficiently stable emulsion to have a storage life of at least 6 months when subjected to storage temperatures in the range of 50.degree.-90.degree. F. (10.degree.-32.degree. C.).
It is an object of this invention to provide a composition suitable for use in airless spray-type equipment such as 17:1 ratio pump sold by Graco and Alemite, etc.
It is a further object of this invention to provide an emulsion composition which can be used in "dip coating" operations. A "dip coating operation" for purpose of this specification involves the process of immersing a part to be coated totally within the composition, removing, and allowing any excess to drip off or flow off from the part, thereby forming a protective film coating thereon.
It is still another object of this invention to provide a coating composition which when formed into a film yields a film which can be both permanent or easily removed. By "easily removed" is meant for purposes of this invention removal by water at a temperature of at least 160.degree. F. (71.degree. C.).
It is another object of this invention to provide a composition that yields a film which provides permanent protection in that it has sufficient water resistance that mere contact with water under ordinary circumstances up to a temperature of 120.degree. F. (49.degree. C.) will not dissolve (situations wherein the film becomes undesirable for its purpose of protection).
It is still another object of this invention to provide both salt spray (ASTM B-117 corrosion test) and humidity protection (ASTM D-1748) in excess of what would otherwise be available in the prior art of any soft film forming water-borne emulsion coating composition.
It is still another object of this invention to provide an emulsion composition for coatings having a Brookfield viscosity according to ASTM D-2196 of about 20,000 cps at 2 rpm to about 30,000 cps both at 77.degree. F. (25.degree. C.) temperature.
Other objects of this invention will be clear to those of skill in the art based upon this specification.